/*
 * Copyright (c) 2024, Alibaba Cloud;
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.aliyun.dataworks.migrationx.transformer.core.spark.command;

import java.io.Serializable;

/**
 * Message definitions for the launcher communication protocol. These messages must remain backwards-compatible, so that
 * the launcher can talk to older versions of Spark that support the protocol.
 */
final class LauncherProtocol {

    /**
     * Environment variable where the server port is stored.
     */
    static final String ENV_LAUNCHER_PORT = "_SPARK_LAUNCHER_PORT";

    /**
     * Environment variable where the secret for connecting back to the server is stored.
     */
    static final String ENV_LAUNCHER_SECRET = "_SPARK_LAUNCHER_SECRET";

    /**
     * Spark conf key used to propagate the server port for in-process launches.
     */
    static final String CONF_LAUNCHER_PORT = "spark.launcher.port";

    /**
     * Spark conf key used to propagate the app secret for in-process launches.
     */
    static final String CONF_LAUNCHER_SECRET = "spark.launcher.secret";

    static class Message implements Serializable {

    }

    /**
     * Hello message, sent from client to server.
     */
    static class Hello extends Message {

        final String secret;
        final String sparkVersion;

        Hello(String secret, String version) {
            this.secret = secret;
            this.sparkVersion = version;
        }

    }

    /**
     * SetAppId message, sent from client to server.
     */
    static class SetAppId extends Message {

        final String appId;

        SetAppId(String appId) {
            this.appId = appId;
        }

    }

    /**
     * SetState message, sent from client to server.
     */
    static class SetState extends Message {

        final SparkAppHandle.State state;

        SetState(SparkAppHandle.State state) {
            this.state = state;
        }

    }

    /**
     * Stop message, send from server to client to stop the application.
     */
    static class Stop extends Message {

    }

}
